skip to main content
OSTI.GOV title logo U.S. Department of Energy
Office of Scientific and Technical Information

Title: Spatial Separation of Carrier Spin by the Valley Hall Effect in Monolayer WSe2 Transistors

Abstract

We investigate the valley Hall effect (VHE) in monolayer WSe2 field-effect transistors using optical Kerr rotation measurements at 20 K. While studies of the VHE have so far focused on n-doped MoS2, we observe the VHE in WSe2 in both the n- and p-doping regimes. Hole doping enables access to the large spin-splitting of the valence band of this material. The Kerr rotation measurements probe the spatial distribution of the valley carrier imbalance induced by the VHE. Under current flow, we observe distinct spin-valley polarization along the edges of the transistor channel. From analysis of the magnitude of the Kerr rotation, we infer a spin-valley density of 44 spins/μm, integrated over the edge region in the p-doped regime. As a result, assuming a spin diffusion length less than 0.1 μm, this corresponds to a spin-valley polarization of the holes exceeding 1%.

Authors:
ORCiD logo [1];  [2];  [1]; ORCiD logo [1]; ORCiD logo [1];  [1];  [1]
  1. Stanford Univ., Stanford, CA (United States)
  2. Stanford Univ., Stanford, CA (United States); Univ. of Texas at Austin, Austin, TX (United States)
Publication Date:
Research Org.:
SLAC National Accelerator Lab., Menlo Park, CA (United States)
Sponsoring Org.:
USDOE
OSTI Identifier:
1507158
Grant/Contract Number:  
AC02-76SF00515; GBMF4545; FA9550-14-1-0040; FA9550-14-0251; 939514; PGSD3-502559-2017; 1741691; 1523883; ECCS-154215
Resource Type:
Journal Article: Accepted Manuscript
Journal Name:
Nano Letters
Additional Journal Information:
Journal Volume: 19; Journal Issue: 2; Journal ID: ISSN 1530-6984
Publisher:
American Chemical Society
Country of Publication:
United States
Language:
English
Subject:
42 ENGINEERING; magneto-optical Kerr effect; spintronics; Tungsten diselenide; valleytronics

Citation Formats

Barré, Elyse, Incorvia, Jean Anne C., Kim, Suk Hyun, McClellan, Connor J., Pop, Eric, Wong, H. -S. Philip, and Heinz, Tony F. Spatial Separation of Carrier Spin by the Valley Hall Effect in Monolayer WSe2 Transistors. United States: N. p., 2019. Web. doi:10.1021/acs.nanolett.8b03838.
Barré, Elyse, Incorvia, Jean Anne C., Kim, Suk Hyun, McClellan, Connor J., Pop, Eric, Wong, H. -S. Philip, & Heinz, Tony F. Spatial Separation of Carrier Spin by the Valley Hall Effect in Monolayer WSe2 Transistors. United States. https://doi.org/10.1021/acs.nanolett.8b03838
Barré, Elyse, Incorvia, Jean Anne C., Kim, Suk Hyun, McClellan, Connor J., Pop, Eric, Wong, H. -S. Philip, and Heinz, Tony F. 2019. "Spatial Separation of Carrier Spin by the Valley Hall Effect in Monolayer WSe2 Transistors". United States. https://doi.org/10.1021/acs.nanolett.8b03838. https://www.osti.gov/servlets/purl/1507158.
@article{osti_1507158,
title = {Spatial Separation of Carrier Spin by the Valley Hall Effect in Monolayer WSe2 Transistors},
author = {Barré, Elyse and Incorvia, Jean Anne C. and Kim, Suk Hyun and McClellan, Connor J. and Pop, Eric and Wong, H. -S. Philip and Heinz, Tony F.},
abstractNote = {We investigate the valley Hall effect (VHE) in monolayer WSe2 field-effect transistors using optical Kerr rotation measurements at 20 K. While studies of the VHE have so far focused on n-doped MoS2, we observe the VHE in WSe2 in both the n- and p-doping regimes. Hole doping enables access to the large spin-splitting of the valence band of this material. The Kerr rotation measurements probe the spatial distribution of the valley carrier imbalance induced by the VHE. Under current flow, we observe distinct spin-valley polarization along the edges of the transistor channel. From analysis of the magnitude of the Kerr rotation, we infer a spin-valley density of 44 spins/μm, integrated over the edge region in the p-doped regime. As a result, assuming a spin diffusion length less than 0.1 μm, this corresponds to a spin-valley polarization of the holes exceeding 1%.},
doi = {10.1021/acs.nanolett.8b03838},
url = {https://www.osti.gov/biblio/1507158}, journal = {Nano Letters},
issn = {1530-6984},
number = 2,
volume = 19,
place = {United States},
year = {Wed Jan 02 00:00:00 EST 2019},
month = {Wed Jan 02 00:00:00 EST 2019}
}

Journal Article:
Free Publicly Available Full Text
Publisher's Version of Record

Citation Metrics:
Cited by: 26 works
Citation information provided by
Web of Science

Save / Share:

Works referenced in this record:

Energy Transfer from Quantum Dots to Graphene and MoS 2 : The Role of Absorption and Screening in Two-Dimensional Materials
journal, March 2016


Improved Contacts to MoS 2 Transistors by Ultra-High Vacuum Metal Deposition
journal, May 2016


High-performance few-layer-MoS2 field-effect-transistor with record low contact-resistance
conference, December 2013


The valley Hall effect in MoS2 transistors
journal, June 2014


Coupled Spin and Valley Physics in Monolayers of MoS 2 and Other Group-VI Dichalcogenides
journal, May 2012


Intrinsic spin Hall effect in monolayers of group-VI dichalcogenides: A first-principles study
journal, October 2012


Electrical control of the valley Hall effect in bilayer MoS2 transistors
journal, January 2016


Giant spin-orbit-induced spin splitting in two-dimensional transition-metal dichalcogenide semiconductors
journal, October 2011


Magnetic brightening and control of dark excitons in monolayer WSe2
journal, June 2017


Spin–orbit coupling in the band structure of monolayer WSe 2
journal, April 2015


Gate-Controlled Spin-Valley Locking of Resident Carriers in WSe 2 Monolayers
journal, September 2017


Valley-dependent optoelectronics from inversion symmetry breaking
journal, June 2008


Control of valley polarization in monolayer MoS2 by optical helicity
journal, June 2012


Exciton valley dynamics probed by Kerr rotation in WSe 2 monolayers
journal, October 2014


Excitonic resonances in thin films of WSe 2 : from monolayer to bulk material
journal, January 2015


Electrical Tuning of Exciton Binding Energies in Monolayer WS 2
journal, September 2015


Charged excitons in monolayer WSe 2 : Experiment and theory
journal, August 2017


Dirac cones and Dirac saddle points of bright excitons in monolayer transition metal dichalcogenides
journal, May 2014


Optical generation of excitonic valley coherence in monolayer WSe2
journal, August 2013


Reduction of hysteresis in MoS 2 transistors using pulsed voltage measurements
journal, October 2018


Measurement of mobility in dual-gated MoS2 transistors
journal, March 2013


Low Variability in Synthetic Monolayer MoS 2 Devices
journal, July 2017


High Mobility WSe 2 p - and n - Type Field-Effect Transistors Contacted by Highly Doped Graphene for Low-Resistance Contacts
journal, May 2014


Valley magnetoelectricity in single-layer MoS2
journal, July 2017


Drift and diffusion of spins generated by the spin Hall effect
journal, August 2007


Optically initialized robust valley-polarized holes in monolayer WSe2
journal, November 2015


Long-Lived Hole Spin/Valley Polarization Probed by Kerr Rotation in Monolayer WSe 2
journal, July 2016


Observation of ultralong valley lifetime in WSe 2 /MoS 2 heterostructures
journal, July 2017